Account for the relationship as it is now
Use a tone that fits the present relationship, not the closeness, authority, or access that existed in the past. For a message about how to ask a co-parent for travel consent, use this factual base: state the child's schedule, health, school, expense, or behavior and distinguish observation from interpretation.
Ask without assigning an obligation
Explain what you hope for while making decline, delay, or a different format genuinely acceptable. Propose a child-focused plan, a response date, and the documented route for unresolved decisions. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Keep the ending honest
Do not use the child as messenger, trade access for agreement, or criticize the other parent to the child. Follow custody orders and use safeguarding, legal, medical, or emergency support for risk to a child. Avoid future promises, guilt, flattery, or nostalgia that imply the recipient owes you access.